Neurotoxicity of 2-bromopropane and 1-bromopropane, alternative solvents for chlorofluorocarbons

To clarify the neurotoxicity of 2-bromopropane (2-BP) in comparison with 1- bromopropane (1-BP), 36 Wistar strain male rats were divided into 4 groups of 9 and exposed daily to 100-ppm 2-BP, 1000-ppm 2-BP, 1000-ppm 1-BP, or fr esh air for 8 h a day. Exposure to 1000 ppm of 1-BP was discontinued after 5 or 7 weeks' exposure because of the unexpected appearance of incomplete h indlimb paralysis followed by serious emaciation. The other groups; were sa crificed at the end of 12 weeks' exposure. Exposure to 1000 ppm of 2-BP res ulted in significant decreases in body weight and motor nerve conduction ve locity (MCV) and elongation in distal latency (DL). A ball-like enlargement of myelin sheaths was observed. Significant reductions in the number of er ythrocytes, platelets, and leukocytes, testicular germ cell loss, and semin iferous atrophy were also observed in this group, but not in 100-ppm 2-BP g roup. Exposure to 1000 ppm of 1-BP for 5 or 7 weeks caused a significant de crease in body weight and MCV and elongation in DL. Linearly arranged ovoid - or bubble-like debris of the axons and myelin sheaths in the teased tibia l nerves and axonal swelling in gracilis nucleus were found in this group. No significant changes in hematological indices or histopathological findin gs of the testis were found in this group. in conclusion, 2-BP is neurotoxi c to the peripheral nerves in addition to its toxic effects on the reproduc tive and hematopoietic systems at 1000 ppm. No noticeable changes were foun d in the rats exposed to 100 ppm of 2-BP, 1-BP is a potent neurotoxicant at 1000 ppm for 5 or a weeks, while testicular and hematopoietic toxicity was not found. (C) 2001 Academic Press.